Masked hypertension (blood pressure that is normal in the physicians' office but elevated elsewhere) is a common phenomenon as prevalence among studies varies from 8 to 45% and is seen at all ages. large discrepancies, however, exist between studies that have dealt with masked hypertension. It is of high clinical importance as it is associated with higher target organ damage as compared with sustained normotension. Therefore more research should be determined. This paper provides an overview of current literature to improve knowledge about masked hypertension and about the cause of this phenomenon. In addition it provides some questions, which need to be answered for performing appropriate research into this subject in future.